
var Widget = Widget || {};

Widget.Utils = Widget.Utils || {};

// NOTE: original source of this code is here: http://ejohn.org/blog/simple-javascript-inheritance/
// Inspired by base2 and Prototype
(function(){
  var initializing = false, fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;


  // The base Class implementation (does nothing)
  this.Class = function(){};
  
  // Create a new Class that inherits from this class
  Class.extend = function(prop) {
    var _super = this.prototype;
    
    // Instantiate a base class (but only create the instance,
    // don't run the init constructor)
    initializing = true;
    var prototype = new this();
    initializing = false;
    
    // Copy the properties over onto the new prototype
    for (var name in prop) {
      // Check if we're overwriting an existing function
      prototype[name] = typeof prop[name] == "function" && 
        typeof _super[name] == "function" && fnTest.test(prop[name]) ?
        (function(name, fn){
          return function() {
            var tmp = this._super;
            
            // Add a new ._super() method that is the same method
            // but on the super-class
            this._super = _super[name];
            
            // The method only need to be bound temporarily, so we
            // remove it when we're done executing
            var ret = fn.apply(this, arguments);        
            this._super = tmp;
            
            return ret;
          };
        })(name, prop[name]) :
        prop[name];
    }
    
    // The dummy class constructor
    function Class() {
      // All construction is actually done in the init method
      if ( !initializing && this.init )
        this.init.apply(this, arguments);
    }
    
    // Populate our constructed prototype object
    Class.prototype = prototype;
    
    // Enforce the constructor to be what we expect
    Class.constructor = Class;

    // And make this class extendable
    Class.extend = arguments.callee;
    
    return Class;
  };
})();


// Original source is from: http://ejohn.org/blog/javascript-method-overloading/
(function() {
	
	this.Class = Class || function(){};
	
	Class.addMethod = function(object, name, fn){
	    var old = object[ name ];
	    object[ name ] = function(){
	        if ( fn.length == arguments.length )
	            return fn.apply( this, arguments );
	        else if ( typeof old == 'function' )
	            return old.apply( this, arguments );
	    };
	}
	
})();

//Simple utilty method to initialize a singleton object
Widget.Utils.initializeSingleton = function(cls, instance, validate) {
	
	// Static initializer
	if (!!validate && typeof(cls._instance) != "undefined") {
		throw new Error("already initizlied");
	}
	cls._instance = instance;

}

// Simple utility method to get a singleton object's instance
Widget.Utils.singletonInstance = function(cls, instantiate) {
	
	if (!!instantiate) {
		if (typeof(cls._instance) == "undefined") {
			Widget.Utils.initializeSingleton(cls, new cls(), false);
		}
	}
	
	if (typeof(cls._instance) == "undefined") {
		throw new Error("not initialized");
	}
	
	return cls._instance;
}

